USPc9 - 14 rounds in magazine?
I just recently moved to a state with no restrictions on magazine sizes and I finally purchased two full capacity magazines for my USP Compact 9mm. Those clips are supposed to be 13 rounds magazines but I tried to fit in more and the magazines hold 14 rounds. Now my question: is it save to load 14 rounds or should rather avoid the extra round? Do I wear out the magazine or risk functioning of the gun by loading the extra round? Anyone else noticed that they can load more ammo in their gun than supposed to?
I would advise not to overload it because the spring was designed to be compressed only so far. While it may fit another round you may be pushing the elastic limits of the spring and ruin it.
Check out HKPRO forum, lots of knowledgeable HK freaks there.
HGF Forum Moderator
I would suggest not to. And, I'll tell you why.
I previously had a 9mm USPc, and a USpc45, along with a P2000 (uses Hk USPc 9mm mags).
I swear - EVERY damn HK magazine spring had issues on my third range trip with the mag (so, as I bought new mags - 3 trips later, that new mag had issues). They would stop locking the slide back when empty...
It is commonly known that the magazine springs on many HK pistol mags are weak.
I was once on the HK Pro website a lot. Many people there just change out the factory springs with Wolf +10% magazine springs when they very first buy a new HK. After a little while, the mags will still work, but no longer lock the slide back when empty.
If you over-stress the springs, you'll reach this point probably much faster - and maybe even make the magazine unreliable totally.
I did not have this issue with the HK45
I never had any problems with the magazines or the slide locking back when empty. I fired at least 10000 rounds through my usp compact and never had issues with the slides locking back. Also , just as a side notice, I never had any malfunction whatsoever with that gun. I also used the HK P8 (german military version of the full size USP) when I was in the german military and I never had any issues with mag or malfunction. Just for the record, with my Glock 19 I had around 15 malfunctions (stove pipes and misfires) since I have it. But only put around 3000 rounds through the Glock so far.
Originally Posted by Shipwreck
Well, I am not going to overload the mags. Was just wondering.
HGF Forum Moderator
All I can say is that between 12 USPc 9mm mags, and like 8 USPc 45 mags, each and every one of them did this to me. It was aggravating... Paying for a replacement spring on top of a high priced magazine to begin with. And, when I was on HK Pro - it was a common occurrence.
I am glad to hear that yours are working fine. I wouldn't jinx it with that extra round if I were you.
I remember the mag spring issue a few years ago but I believe it's been resolved since then. I can't recall but I think it was isolated to around a year or 2 period of spring manufacture.
Generally, a magazine is designed to hold what the magazine is designed to hold. The magazine spring needs a little room to work and as you can imagine that last round is practically at the bottom of the magazine with the spring perhaps compressed beyond it's design. I've heard some using .40 cal mags in their USPc 9's to get more rounds, but the overall consensus was for range work only. I'd suggest the same, for range work only, or if you can test over a fairly broad time frame that 14 rounds will work reliably and that the spring holds up then maybe I'd consider it for a SD role. I want to say that the spring you have is perhaps a smaller diameter spring than lets say a "wolf" HP spring for the same application. I've played around with shotgun extended magazine tubes and springs where the thinner spring of the same length will allow 8 shells of 2 3/4 and the HP thicker spring of the same exact length will not. In other words the thinner diameter spring allows for further compression. This is not scientific, just an observation.
Originally Posted by Gebirgsjäger